BOSTON -- Isaiah Thomas often stands by himself in the corner of the floor opposite the Boston Celtics' bench during pregame introductions. Maybe it's his size, but the 5-foot-9 point guard typically blends into the on-court scenery until his teammates finally turn in his direction and acknowledge him when his name is the final one called.

But on Sunday night, Thomas stood on the corner of the TD Garden floor looking remarkably vulnerable. With tears in his eyes, Thomas did not raise his hand like he typically does when his name is announced, nor did he bound into Boston's huddle to engage in the typical pregame mosh pit.

Instead, Thomas walked solemnly toward his teammates, who swallowed him into what was essentially a gigantic group hug. A deafening roar filled TD Garden, and a sign behind the Boston bench hammered home the theme of the night:

"We got you, Isaiah."

On an emotional night for him, Isaiah Thomas went for 33 points in the Celtics' Game 1 loss. Brian Babineau/NBAE via Getty Images

One day after his sister died in a car crash, Thomas improbably scored a game-high 33 points, but the top-seeded Celtics fell to the eighth-seeded Chicago Bulls106-102 in Game 1 of an Eastern Conference first-round series.

Emotionally exhausted, Thomas elected not to speak with reporters following Sunday's game. But teammates and coaches marveled at the way he competed despite what he is going through. Their only lament was that they hadn't found a way to get a win for Thomas.

"I think it just speaks to who he is as a person and how he comes out here and just fights each and every night, even when adversity is against him," Celtics forward Jae Crowder said. "We just should have gotten that win for him."

Celtics coach Brad Stevens visited with Thomas on Saturday night and stressed to him again Sunday that he did not have to play if he did not feel up to it. Little more than 24 hours had passed since Thomas learned that his 22-year-old sister, Chyna Thomas, had died in a one-car interstate accident in their home state of Washington.

Thomas was caught by TNT's cameras sitting on the sideline following Boston's afternoon walkthrough with his head buried in his arms. Avery Bradley, a fellow Tacoma native who was with Thomas when he learned of his sister's death Saturday, went over to again console his friend.

Four years ago, Bradley lost his mother, who was 46, and her death hit him hard before the start of training camp that season. As Stevens noted, there's no script for dealing with situations such as this, and Bradley tried to simply comfort his friend.

"Isaiah, to me, he's family," Bradley said. "We grew up in the same area. I know it's tough for him. It says a lot about him. It says he's a true competitor. I know tonight he was playing for his sister. He was playing for his family.

"We appreciate that as teammates, and he's just an amazing basketball player and even a better person. I'm happy with the way he played tonight, and we just need to continue to fight for him."

Thomas led the Celtics onto the court before Sunday's game, and Boston fans roared when he emerged from the tunnel. Thomas looked emotional simply trying to navigate layup lines, then tears ran down his face when the Celtics held a moment of silence for his sister before Sunday's national anthem.

Penned on the side of Thomas' green high-tops were "Chyna," "RIP LIL SIS" and Saturday's date.

2017 NBA Opening Night

On opening night, the Warriors were stunned in Oakland and the Celtics' high hopes took a tumble.

As exhausted as Thomas looked emotionally, there were times Sunday when basketball seemed like a welcomed three-hour diversion. Thomas scored 13 first-quarter points in an 11-minute stint, with the crowd responding with standing ovations both for his first bucket and when he checked out of the game.

Thomas could not prevent the Celtics from letting Sunday's game slip away. Boston struggled on the glass, getting outrebounded 53-36, and the Bulls turned 20 offensive rebounds into 23 second-chance points.

Game 2 is Tuesday night at TD Garden, and Stevens said he would allow Thomas to determine whether he wants to play or be with his family in Washington.

"Whatever he needs to do, he needs to do, and we'll help in any way," Stevens said.

Boston players didn't want to use Thomas' situation as an excuse but admitted that Sunday's game was difficult because of what Thomas is enduring.

"We're never going to make excuses, but this was hard," Al Horford said. "This was difficult, and I felt like our guys really dealt with it the right way. Isaiah's the one I feel like was the best. We knew he was hurting, and it's not easy, and we have a lot of respect for him. We have a lot of respect for what he's able to do to come out here and show -- it's not an easy task."

Added Crowder: "It was a little awkward for us. But we tried to put that behind us and fight for him. But it was a little off. Because you wanted to talk to him, but you really can't talk to him because he's not talkative right now. He's just fighting through some adversity. And that's understandable."

BOSTON CELTICS

CHICAGO BULLS

"I think he handled [the situation] great. It's a tough question, bro," Gerald Green said. "I mean, he just lost his sister. So I don't know. I don't know how anybody could handle that. ... IT is unbelievable. There's nothing that he does that surprises me anymore."

The challenge for the Celtics now is to push forward in this series while trying to support Thomas.

"It's our job as a team to make sure that we're there to support him and keep him positive and just playing as hard as we can for him," Bradley said. "I think that's the main goal for everyone in this locker room."